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Biomedical subjects

D Baker

Publications and source records attributed to D Baker.

At least 343 records · Page 19Linked to original sources
PubMed1985

Effect of depletion of epidermal dendritic cells on the induction of contact sensitivity in the guinea-pig.

Guinea pig skin was depleted of Langerhans cells (LC) as assessed by ATPase and Ia staining using several techniques. The LCs were depleted either by tape-stripping or exposure of the animals to UV-B or UV-C radiation. Guinea-pigs were sensitized to 2,4-dinitrochlorobenzene (DNCB) by application of the sensitizer to the epidermis depleted of LC. Minimally suppressed contact reactions were found in animals exposed to both wavelengths of radiation, but this was shown to be a systemic rather than a local effect. Tape-stripping did not alter the degree of contact sensitivity when guinea-pigs were sensitized with a large dose of DNCB. When a non-sensitizing dose of DNCB was applied to the ear depleted of LC by tape-stripping, contact sensitivity resulted. Although the depletion of LCs was 97% following UV-B, 93% with UV-C and 78% after tape-stripping, at no time were LCs completely absent from the epidermis.

Animals↗
PubMed1985

Renal pathology of prenatally diagnosed nephrosis.

Congenital Finnish nephrosis is a rare autosomal-recessive disorder, usually fatal at an early age. The disease is prenatally detected through elevation of alpha fetoprotein in the amniotic fluid of pregnancies at risk. This originates from fetal proteinuria. Maternal serum alpha fetoprotein reflects amniotic fluid levels. We describe a case of congenital nephrosis diagnosed through maternal serum screening in a low-risk population. The characteristic histology of congenital nephrosis is demonstrated, and evidence of proteinuria by electron microscopy, light microscopy, and immunofluorescence is presented.

Adult↗
PubMed1985

Microprobe analysis in human pathology.

This tutorial paper reviews the literature on the application of microprobe analysis to practical problems in diagnostic human pathology. The goal is to allow the reader ready access to the literature on specific clinical problems. Specimen preparation and commonly encountered artifacts are also considered. It is concluded that energy dispersive x-ray microanalysis and back-scattered electron imaging are at present the most generally useful microprobe techniques for clinical work, and are no longer solely research tools. The findings often have diagnostic, therapeutic, and/or legal implications.

Body Fluids↗
PubMed1985

A multicenter comparison of related pharmacologic features of cephalexin and dicloxacillin given for two months to young children with cystic fibrosis.

Twenty-one cystic fibrosis patients under 3 years of age were enrolled in an open multicenter study to assess the feasibility of the study design and to compare selected pharmacologic features of cephalexin or dicloxacillin administered orally for 2 months. Patient tolerance and compliance were significantly less for dicloxacillin (p less than .01 and p less than .001, respectively). Superficial Candida infections were more common in the cephalexin group (p = 0.02), however increased stool frequency and nonspecific diaper rashes were more prevalent in patients receiving dicloxacillin (p less than .05). Staphylococcus aureus was isolated from respiratory secretions after 2 months from two dicloxacillin and no cephalexin patients. Areas under the curve and peak serum concentrations were higher for cephalexin (p less than .05 and p = .02), but antistaphylococcal activity in serum was higher for dicloxacillin (p less than .05) due to a lower mean MIC compared to cephalexin. Deep pharyngeal plus routine throat culture yielded more pathogens than either method alone. Express mail and central processing of respiratory specimens was efficient for most organisms, however there was some loss of Streptococcus pneumoniae and Haemophilus influenzae. Cephalexin was associated with better patient acceptance and compliance despite higher rates of superficial fungal infections as compared to dicloxacillin. Cephalexin, routine bacteriologic throat swabs processed locally or centrally, mail-in urine compliance assessment and a multicenter design are feasible components for a long-term prospective evaluation of antibiotic prophylaxis in patients with cystic fibrosis.

Administration, Oral↗
PubMed1984

The influence of infused calcium on the postischemic myocardium.

Despite evidence for calcium-induced damage in the postischemic myocardium, calcium remains a frequently used inotropic agent following cardiopulmonary bypass surgery with cardioplegic arrest. The purpose of this study was (1) to challenge the postischemic myocardium with incremental doses of ionized calcium, and (2) to relate postischemic calcium reperfusion concentration to final recovery of left ventricular contractile function. Rabbit hearts (N = 38) were perfused and equipped with a ventricular balloon to monitor developed pressure (DP) +/- dp/dt, and left ventricular end diastolic pressure (LVEDP). Hearts underwent 40 min of global ischemia. Hearts were then assigned to one of four groups to receive a variable calcium concentration (0.6, 1.2, 2.5, 5.0 mM) for the initial 5 min of reperfusion followed by 55 min of reperfusion (Ca+2 = 1.25 mM). No differences were found between groups for final recovery of DP +/- dp/dt, or final LVEDP. It was concluded that: (1) within the physiologic range, variable calcium infusions during the first 5 min of postischemic reperfusion do not impair final recovery of LV contractile function, (2) irreversible partial recovery of left ventricular function appears due to mechanisms other than mitochondrial or myofibrillar calcium loading during reperfusion, and (3) infused calcium is a safe inotropic agent even in the postischemic myocardium.

Animals↗
PubMed1984

Eyelid and orbital treatment following radical maxillectomy.

Malignant lesions of the nasopharynx and paranasal sinuses often encroach upon the orbit. A series of nineteen patients who underwent partial or radical maxillectomy is presented to summarize the eyelid and orbital findings that required further treatment. Fifteen of these patients were left with an intact globe and a visually useful eye, but the defects of epiphora, eyelid malposition, dacryocystitis, and diplopia were visually threatening and required treatment. The cosmetic deformities and diplopia following maxillectomy and radiation are partially amenable to treatment with late bone grafting. Lacrimal outflow deficiencies were successfully treated with dacryocystorhinostomy. Only patients with ocular complications following maxillectomy are included in this series; therefore, the range of problems and their treatment confronting the ophthalmologist is summarized.

Adenocarcinoma↗
PubMed1984

Response of previously irradiated skin to combinations of x radiation, hyperthermia, and cis-diamminedichloroplatinum.

Mouse legs were irradiated to a dose of 30 Gy. After 50 days, when the acute reaction had regressed to a steady state, they were retreated with either various doses of x rays (15 to 30 Gy), hyperthermia, 45 min at 42.7 degrees C, cis-DDP, or a combination of these agents. The maximum skin reactions and the skin reactions integrated over 50 days were determined. Statistical analysis of these data indicated the thermal enhancement ratio for the previously irradiated skin was approximately 1.20. The combination of x irradiation, hyperthermia, and cis-DDP treatments to the previously irradiated skin did not enhance the radiation damage beyond that produced by x irradiation and hyperthermia.

Animals↗
PubMed1984

The natural history of spondylolysis and spondylolisthesis.

We performed a prospective roentgenographic study to determine the incidence of spondylolysis, spondylolisthesis, or both, in 500 unselected first-grade children from 1955 through 1957. The families of the children with spondylolysis were followed in a similar manner. The incidence of spondylolysis at the age of six years was 4.4 per cent and increased to 6 per cent in adulthood. The degree of spondylolisthesis was as much as 28 per cent, and progression of the olisthesis was unusual. The data support the hypothesis that the spondylolytic defect is the result of a defect in the cartilaginous anlage of a vertebra. There is a hereditary pre-disposition to the defect and a strong association with spina bifida occulta. Progression of a slip was unlikely after adolescence and the slip was never symptomatic in the population that we studied.

Adolescent↗
PubMed1983

A new technique in quantitative immunohematology: solid-phase kinetic enzyme-linked immunosorbent assay.

A solid-phase kinetic enzyme-linked immunosorbent assay has been developed to measure binding of antibodies to purified or synthetic blood group antigens and tested in the Lewis blood group system. Chemically synthesized Lewis a antigen is used as the target for the binding of serum antibody in this sandwich-type assay. Kinetic, rather than endpoint, determinations are used to calculate the amount of specific antibody. Data are presented showing the assay to be quantitative, sensitive, and specific. It can separately quantitate the amount of IgG or IgM anti-Lewis a present in patient sera. The assay uses commercially available reagents and is semiautomated. Thus, it will be useful for studies in quantitative immunohematology as other blood group antigens become available in purified form.

Antibody Specificity↗
PubMed1983

The effect of ultrasound-induced hyperthermia and X irradiation on skin.

Local hyperthermia for up to 60 min at 42.5-43.0 degrees C was induced in the skin of the mouse leg using ultrasound (780 kHz, 0.5-2.0 W/cm2). X radiation at doses of 10 to 30 Gy was delivered either before, during, or after the hyperthermia and the skin reactions were followed for 50 days. The thermal enhancement factor (TEF) was estimated using three criteria: (1) the maximum skin reaction; (2) the skin reaction integrated over the 50-day experimental period; (3) the skin reaction integrated over Days 8 to 32, which have a larger estimate. The TEF was independent of the sequence of heat and X radiation for intervals up to 1 hr. For 1 hr of hyperthermia, the TEF as measured by the maximum skin reaction did not change with radiation doses of 10 to 20 Gy. When the skin reaction integrated over 50 days or Days 8 to 32 was used as the criterion of response, the TEF varied with radiation dose from 4.7 at 10 Gy to 1.6 at 20 Gy. For a fixed radiation dose of 20 Gy, the TEF was not increased significantly by extending the duration of the hyperthermia from 30 to 60 min. The TEF for a radiation dose of 20 Gy delivered in three fractions over 5 days was smaller than that for a single 10-Gy fraction.

Animals↗
PubMed1982

The influence of warfarin of levamisole on the incidence of metastases following local irradiation of a solid tumor.

KHT sarcomas were implanted in the right rear legs of C3H mice. An x-ray dose of 6000 rad, delivered in ten equal fractions over 12 days, resulted in 60% local tumor control, but 83% of these mice developed metastases. Three strategies to use the tumoricidal effect of x-radiation and reduce the incidence of metastases were compared. A modification of the fractionation scheme to deliver an initial large fraction of 1800 rad followed by seven 600-rad fractions resulted in a decreased incidence of metastases compared with the same dose delivered in ten equal fractions. The use of warfarin anticoagulation during the ten-fraction course of radiation resulted in a small decrease in the incidence of metastases. Immune stimulation with levamisole, injected subcutaneously every second day during the irradiation, also resulted in a decrease in the incidence of metastases. However, when warfarin or levamisole were combined with the eight-fraction radiation scheme there were fewer metastases than following the ten-fraction scheme. The combination of the eight-fraction radiation course with levamisole also produced a significant increase in primary tumor control. In this treatment regimen, therefore, levamisole appears to act as a radiation sensitizer. An hypothesis to explain this action is proposed.

Animals↗